REVAMPING OF 23 YEARS OLD UREA PLANT AT IFFCO KALOL

Revamp of Chemical Fertiliser Plants is an economically attractive proposition as grassrootplants are large capital intensive ventures. This paper illustrates a successful attempt inrevamping urea plant capacity by 37.5% with special emphasis on selection of scheme andimplementation, the two crucial steps in achieving the final goal.

V.S. VAISH & A.B. SARKAR

IFFCO Kalol Unit, Dist.Gandhinagar Gujarat, India

PREAMBLE

Indian Farmers Fertiliser Cooperative Ltd (IFFCO), is a premier Co-operative Society, engaged in business ofmanufacture and marketing of chemical fertilisers in India. The annual installed capacity is 3.2 Million Tonnes ofUrea and 1.2 Million Tonnes of NPK/DAP with Annual total revenue of US $ 810 Million.

IFFCO Kalol Unit operates Ammonia & Urea Plants of MW Kellogg and Stamicarbon design respectively since1974. In 1997, after running the plants for almost 23 years, Ammonia plant capacity has been increased fromoriginal designed capacity of 910 MTPD to 1100 MTPD and Urea Plant capacity from original designed capacity of1200 MTPD to 1650 MTPD.

The principal criteria of justifying revamp of any vintage plant is endorsement of the sound health of criticalequipment and piping of the plant. Urea Plant at IFFCO Kalol was constructed by Humphreys & Glasgow, UK(now known as Jacob H&G) on turnkey basis in 1973-74 based on CO2 stripping total recycle process, developed by Stamicarbon bv of The Netherlands. In any Urea plant, high pressure equipment such as Urea Reactor, Stripper, Condenser, Scrubber,CO2 Compressor, Ammonia Pumps, Carbamate Pumps and interconnecting high pressure piping are critical andtheir health determines the residual life of plant and so the justificaton of revamp. At Kalol, all critical equipmentare the original ones except the high pressure Condenser which was replaced in September 1993. The highpressure equipment are inspected routinely by in-house inspection group with periodic inspection by Stamicarbon.

The sound health of these critical equipment prompted IFFCO to think of a cost effective revamp of the Urea Plant.It is worth mentioning at this point that the Stripper, the most corrosion / erosion prone equipment in any Ureastripping process, is in service at IFFCO Kalol for 25 years, longest ever for any such equipment. Recent inspection of this critical equipment carried out in April 1998 reveals that the Stripper still has a residual life of 3 to4 years. Considering this fact, action has already been initiated for replacement of this critical equipment in nearfuture. Inspection history and health of high pressure equipment in Urea plant prior to taking up of revampingactivities in March 95 is projected in TABLE-1.

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Corrosion rate observed 0.04 mm/yr which is normal.Weld defects observed on tube to tube sheet.Rectified by grinding and filling as per standardprocedure.

Shell & tube heat exchangerYear of Fabrication - 1972Liner & tube materialX2 CrNiMo 17.13.2 Urea Gr.Tube OD 25 mm Tube Thk - 2.5 mmNo. of Tubes 424 `U’ tubes

Scrubber4.

Corrosion rate is 0.06 mm/yr which is normal.Average tube thickness is 2.68 mm. Tube sheet andoverlay condition are OK. Liquid entry holes on gastubes (ferrules) increased from 2.3 mm to 2.5 - 2.6mm.

Shell & tube heat exchangerYear of Fabrication - 1972Liner & tube materialX2 CrNiMoN 25.22.2Tube OD 32 mm Tube Thk - 3.5 mmNo. of Tubes 2100

Stripper3.

The equipment replaced by a new one in 1993.Material of construction of Tubes and Liner changedto X2 Cr NiMoN 25-22-2 from SS 316 L Urea Gr. Internals are almost like new after 3 years ofoperation.

Shell & tube heat exchangerYear of Fabrication - 1992Liner & tube materialX2 CrNiMoN 25.22.2Tube OD 25 mm Tube Thk - 2.5 mmNo. of Tubes 1970

Condenser 2.

Good liner condition. Bottom hemispherical linersegment replaced due to leakage of nozzle - linerweld. Corrosion rate is 0.03 mm/year which isnormal. All internals are in good condition. Welddefects observed on longitudinal and transversalweld of liner and tray support. Affected area grinded and rewelded as per standard procedure.

VesselYear of Fabrication 1972Liner material 316L Urea GrX2CrNiMo 17.13.2 Urea GrLiner Thickness - 5 mmTrays - 10

Reactor1.

Health StatusDescriptionHighPressure Equipment

SlNo

Table-1

SELECTION OF REVAMP PROCESS

Revamp schemes are normally tailor made for a particular plant. In-built capacities of existing equipment areassessed for provision of minimum number of additional equipment to meet the targeted enhanced capacity of theplant. No revamp scheme has any reference to find provenness and reliability. This makes it more difficult to choosethe perfect revamp scheme. In case of Kalol Urea plant it was capacity expansion from 1200 MTPD to 1650MTPD (increase of 37.5%). The revamped capacity of 1650 MTPD was firmed up based on preliminary end to endsurvey of Urea plant carried out by Stamicarbon in early 1994. The concept was based on “MORE-IN-MORE-OUT”philosophy taking advantage of maximum cushions available in various process equipment and supplementing deficitareas by modifications and replacement of certain equipment and creating some add-on facilities keeping safety andeconomy in view. While reviewing the technology options following basic criteria was kept in view.

• Minimum equipment so as to manage within the space available• No change in operating philosophy• Low investment per tonne of urea• Low emission levels and specific energy consumption per tonne of urea produced

• Minimum down time to hook-up new equipment and add on facilities• No additional steam requirement for increased plant capacity

2There were two options available for selection of process consultant. Both the technologies were based on “MORE-IN-MORE OUT” concept for same enhanced capacity but one of the consultants proposed add-on facilities consisting of complete Medium Pressure Section operating at 18 ata pressure in addition to modifications andreplacement of certain equipment.

Revamp scheme of Stamicarbon was chosen based on the following three important factors :

1. Minimum number of additional equipment as compared to the offer of other competitor. This was veryimportant because existing plant with vertical layout and built in space of just half the area (4200 M2) ascompared to new generation plants had hardly any space left for placement of new equipment. This factor wasvery much realised during erection of new equipment and related piping.

2. Stamicarbon being the original process licensor had access to up-to-date data of Kalol Urea Plant. Their offerwas perfectly tailor made for the revamp option, taking into consideration all the limitations including severespace constraint.

3. Confidence level of proven technology through original plant designer. Stamicarbon had been involved in allmajor trouble shooting activities right from commissioning of the plant in 1974 and inspection of criticalequipment during various annual turnarounds.

Process flow diagram of the plant is shown in Fig-1 highlighting new equipment added with dotted lines.

CONSULTANCY AND CONSTRUCTION AGENCIES

The revamp project was approved by the Government with zero date as 1st March 1995 and completion within 30months. Before signing the agreement with the Process Licensor, Stamicarbon was entrusted the job for carrying outdetailed Urea plant study. This was necessary to know the bottlenecks and plant capability to produce 1650 MTPDon continuous basis. The agreement for supply of “Basic Process Design package (BPDP)” and other engineeringservices was initialled in September 1995 with Stamicarbon. For providing Design, Engineering & Procurement(DEP) and site supervision services, agreement was made with Stamicarbon’s approved Indian Consultant Tecnimont ICB (TICB).

Construction and erection jobs were entrusted to reputed agencies like L&T (Mechanical Contractor), GannonDunkerley (Civil Contractor), AEC (Electrical Contractor) & Blue Star (Instrumentation Contractor).

ENGINEERING AND EXECUTION

During the kick-off meeting between the Process Consultant, Indian Consultant & IFFCO following parameters /responsibilities were discussed and agreed.

• Scope of Process Consultant under Basic Process Design Package (BPDP) & Scope of Indian Consultantduring various stages of project execution.

• Lay-out of new equipment

• HAZOP study of high pressure section by Process Licensor and remaining portion by Indian Consultant.

• Parameters for performance guarantee

• Overall Project Schedule

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The remedial measures implemented in various sections to achieve the design capacity of 1650 MTPDare summarised in Table 2 and also described individually in the following text.

• Old pneumatic instrumentation was changed to electronic basedinstrumentation

DCS Based Instrumentation5

• Installation of pre-evaporator• Replacement of evaporator, condenser and ejector in 1st and

2nd vacuum evaporator system• Replacement of prill machine with modified prill bucket.

Evaporation & Prilling4

• Modification in recirculation heater of rectifying column• Additional condenser • Increase of plates in plate heat exchanger• Modification of operating system of flash tank• Improved scrubbing of ammonia• Addition of one small capacity ammonia - water tank

Low Pressure Section3

• Installation of CO2 centrifugal compressor.• Installation of one HP ammonia pump & replacement of

turbines of old pumps with motors.• Installation of one HP carbamate pump & replacement of

turbines of old pumps with motors.• Replacement of high pressure discharge pipes of ammonia and

carbamate pumps

Feed Pumping/Compression2

• Installation of modified trays in reactor • Chemical cleaning of HP stripper tubes & modification to

liquid distributors• Reduction in LP steam generation pressure

in HP condenser• Reduction of passivation air in HP system• Installation of N/C ratio meter• Adoption of low pressure start up

High Pressure Section1

DescriptionAreaSlNo

Table-2HIGH PRESSURE SECTIONUrea Reactor

Harnessing the capacity of Urea Reactor which had 10 trays of original Stamicarbon design was important to achievehigher conversion compatible with enhanced plant capacity. Prior to revamping, conversion efficiency of the reactorwas in the range of 58 to 59%. To achieve conversion efficiency in the range of 61 to 62% and with an ultimate aimto produce plus 1650 MTPD, original trays were replaced with 11 Nos modified trays fabricated and supplied by

Schoeller Bleckmann of Austria based on Stamicarbon proprietary design. Overflow pipe inside the reactor was alsoreplaced with bigger size pipe to meet the requirement of higher flow rate.

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H.P. Stripper

HP Stripper which has 2,100 tubes is in service for past 25 years. However, hard scale deposit mainly of iron oxideof 2-2.5 mm thick got deposited inside the vertical tubes predominantly on lower part. It was almost impossible toremove this hard scale by mechanical means i.e rubbing with brush or hydrojetting. This was the cause of gradualdecrease of Stripper efficiency, to a level of about 75 to 77% due to poor heat transfer. To improve the strippingefficiency HP Stripper was chemically cleaned with EDTA solution by Stamicarbon recommended agencyHouseman Metal Cleaning bv of The Netherlands. Around 1.8 tonnes of hard scale was removed, thus improving thestripping efficiency by about 2%.

To improve the liquid / gas distribution in stripper tubes, flow dividers were provided with orifices on all ferrules.The holes on old gas tubes which got enlarged due to long service of 23 years were good enough for enhancedcapacity, therefore the same ferrules were used with slight modification. Currently the same old stripper is in servicesto produce more than 1650 MTPD.

H.P. Condenser

At uprated capacity, the L.P. Steam generation pressure on shell side was reduced from 3.6 kg/cm2g to 3.2 kg/cm2gto augment the additional duty in HP Condenser. For flexibility in operation, the pressure control valve installed atthe outlet of steam drum has been shifted to the export steam header.

H.P. Scrubber

Air feed for passivation purpose was reduced with respect to O2 content from 0.8%(v/v) to 0.6% (v/v) as per recentstandard of Stamicarbon process, reducing the inert content by 25% in synthesis section. This resulted inavailability of more effective volume in reactor due to less accumulation of inert and also less loss of ammoniaalong with the inert through final venting. The heat load on H.P. Scrubber remained almost the same at the enhancedcapacity of 1650 MTPD, hence no modification was required in the H.P. Scrubber.

N/C Ratio Meter

At the uprated plant capacity it was but for sure that operating flexibility will be squeezed. To avoid process upsets,N/C Ratio Meter developed jointly by Stamicarbon & ThIS Analytical b.v. of The Netherlands has been installed to monitor NH3/CO2 mole ratio in the reactor.

This is the first time that such an instrument is installed in India for precise control of a critical parameter inachieving ideal operating condition in Urea plant.

Low Pressure Start up

To shorten the start-up time and to avoid the severe noise pollution, which is a serious problem in an oldStamicarbon Urea Plant, modification has been carried out to adopt steam passivation and low pressure start-up.Originally recommended passivation and heating of HP System by CO2 at 60-70 kg/cm2 mixed with 1.00% (v/v)

anti-corrosion air has been replaced by 9 ata steam heating and passivation system. By adopting this change thepassivation period is reduced from 14 Hours to 4 Hours and during this period CO2 Compressor is not required tobe run giving direct benefit of energy saving and pollution free start-up.

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FEED PUMPING/COMPRESSION

CO2 Compressor

Before revamping, Kalol Urea Plant was operating with two (1+1) reciprocating compressors of Peter Brotherhood, U K and GHH, Germany with a common Centrifugal Booster Compressor for meetingrequirement of compressed CO2 in Urea plant. These compressors were capable to compress CO2 for production ofmaximum 1350 MTPD urea on sustained basis. For meeting the additional requirement of CO2 following options were studied in detail:

1. Enhancing the capacity of existing compressors.2. Installation of small reciprocating compressor in parallel.3. Running both the existing compressors in parallel at low load.4. Installation of a centrifugal compressor of capacity equivalent to 1650 MTPD.

Out of various alternatives, it was decided to opt for full capacity centrifugal compressor to economise on steambalance and to eliminate additional power requirement to the tune of 1920 KW. Moreover, installation of centrifugalcompressor would ensure greater reliability in operation and provide high on-stream factor, reduce down time andmaintenance cost. Full capacity centrifugal compressor is procured from Hitachi, Japan.

H.P. Ammonia & Carbamate Pumps:

Prior to revamping, Kalol Urea Plant was operating with two (1+1) reciprocating Worthington make HP AmmoniaPumps each capable of delivering maximum of 60 M3/Hr of Ammonia and two (1+1) reciprocating Worthingtonmake HP Carbamate pumps each capable of delivering 28 M3/Hr of carbamate. The pumps were equipped with steam turbine drives except one Ammonia pump which was equipped with motor. Initial option was to change theturbines with motor drives to match the steam balance in Urea plant and to run both ammonia and carbamate pumpsin parallel at reduced capacity so as to get the desired combined flow of ammonia and carbamate for revamped plantload. However, this arrangement would have left no spare Ammonia and Carbamate pumps for this critical service.Options were many such as to add similar capacity one number each ammonia and carbamate pumps of reciprocatingtype and run two pumps in parallel at reduced load with one pump as standby. Another alternative was to havecentrifugal type one number each ammonia and carbamate pumps for full capacity and keep the existingreciprocating pumps as standby. All these alternatives were well deliberated from the view point of economicconsiderations, change in operating & maintenance philosophy and high operating cost. Both these alternatives werefound not suitable to our system and also economically not viable as in both the cases pumps would have got muchexcess capacity never to be utilised and also motors needed 3.3 KV rating power supply, the network of which wasnot available within the Urea plant battery limit.

Ultimately the best option emerged out is given below:-

1. Derate the existing capacity of Ammonia pumps from 60 M3/Hr to 45 M3/Hr limiting the maximum speed andadd one new smaller size pump of 45 M3/Hr capacity with (2+1) operating philosophy.

2. Derate the existing capacity of reciprocating Carbamate pumps from 28 M3/hr to 22.5 M3/hr and to add a newsmaller size pump of 22.5 M3/Hr with (2+1) operating philosophy.

3. Remove steam turbines and change all the pumps to variable frequency AC LT motor drive system which woulddirectly give an annual saving of Rs. 9.5 Million (US $ 223500) on operating cost with respect to other options.

One number each reciprocating type new Ammonia and Carbamate pumps and variable frequency AC LT motor drive system for existing 2 Nos Ammonia and 2 Nos Carbamate pumps were procured from

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Peroni, Italy. The combination of old and new pumps are running smoothly, moreover 23 year old pumps atreduced speed has resulted in less wear and tear of the pumps and longer life of the packing and valve assemblies.Complete Analogue study of both Ammonia and Carbamate pumps including piping was also carried out beforesupply of new pumps and frequency variable drives of existing pumps. This study was essential as this type ofarrangement has no reference and is adopted for the first time in the world where two dissimilar new reciprocatingpumps are added to the existing pumps with de-rated capacities. Again IFFCO Kalol is the first plant in India wherefrequency variable AC LT motor drive system has been tried successfully on H.P. Ammonia and Carbamate pumps.

High Pressure Piping

Discharge piping of both H.P. Ammonia & Carbamate Pumps which were 23 years old, have been changed from 4”to 6” and 3” to 4” sizes respectively from reliability point of view and to accommodate the enhanced flow rates withpermissible pressure drops.

LOW PRESSURE SECTIONRecirculation heater Modification

LP Decomposer heater is a vertical heat exchanger where process stream is heated by 4 ata steam. Driving force forprocess fluid movement is by thermosyphonic action. Requirement of higher heat transfer to meet revamp capacityheat load needed replacement with bigger size heat exchanger. An innovative method was adopted to increase theheat transfer rate by installing orifices at the bottom of each 1030 vertical tubes. The orifices act as an ejectorthereby increasing velocity of process fluid and higher heat transfer rate by about 30%. The modification adopted isshown in Fig. 2

LP Condenser in series to existing L.P. Condenser

The best and most economical option to make up shortfall of condensing capacity of vapour in low pressure section was to install an additional L.P. Condenser in series to the existing L.P Condenser rather than going for singlebigger capacity condenser. The new condenser is falling film type capable to remove additional heat duty of 30%due to increase in process vapour load at enhanced capacity. The equipment was procured from L&T. Erection ofthe equipment was at the height of 18 meters by the side of old condenser to have the minimum pressure drop . TheRCC columns were up to height of 7 meters only which were strengthened by reinforcing them. Structuralframework was then erected above the reinforced columns to accommodate the equipment at 18 meters height.

Plate Heat Exchanger Modification

Heat of condensation in low pressure system is removed by closed loop circulating condensate which releases theheat to cooling water in plate type exchanger. Additional 46 no. of plates are added to increase the capacity of theexchanger to meet the higher heat load.

Flash Tank

Flash Tank is last purification stage for removing traces of ammonia & CO2 from main product stream. To reduceload on Hydrolyser and also to ensure admission of less quantity of water to the system, operating pressure ofFlash Tank was changed from vacuum to atmospheric pressure. Flashed condensate containing substantial ammonia recycled back to L.P. System for recovery of ammonia instead of sending to Hydrolyser section through WasteWater Tank.

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Improved Scrubbing system

Existing scrubbing of ammonia to reduce loss to atmosphere is improved by higher flow rate of lean ammonia watersolution to the scrubbers and recovery of vent gases from low pressure section by diverting the gases to flash tankcondenser. By this modification, ammonia losses are restricted to 0.4 kg/te of product only.

Ammonia Water Tank

One 15 M3 capacity small tank is added by the side of main tank for the purpose of separating lean ammonia water(4% NH3 conc) received from evaporation section and strong ammonia water (7% NH3 conc) after scrubbing ofammonia from HP & LP System. This improves the scrubber performance.

EVAPORATION AND PRILLINGPre-Evaporator

To harness the overall capacity of evaporation section for handling increased production, Pre-Evaporator,Pre-Evaporator Condenser and associated piping and instrumentation have been installed to increase urea solutionconcentration from 72% to 82% in Urea Solution Tank utilizing the heat from process. The evaporator package withtwo heat exchangers in series (one part for heat transfer with process heat i.e. heat of condensation recovered fromHP Scrubber and another part for heat transfer with 4 ata steam generated from process heat in HP Condenser) wasprocured from GR Engineering, Mumbai and Vacuum Condenser from Graham USA. Evaporator Section withPre-Evaporator is shown in Fig-3. Erection of the equipment weighing around 120 Tonnes was a difficult task asplacement of the equipment was at a height of 18 - 25 meters with minimum process flow path to prevent highBiuret formation. Finally some old civil engineering drawings revealed existence of civil foundations and structureon North West side of Prilling Tower which was meant for bucket elevator system abandoned and removed around18 years back. Structural columns of this area were strengthened by encasing with additional structuralcolumns. The existing encased structures were extended to accommodate the complete package at a height of 18 - 25 meters. In addition to above, following changes have also been incorporated:

• Increase in capacity of urea solution tank by adding a smaller tank by the side of existing tank,• Replacement of existing urea solution pumps with higher capacity suitable for higher concentration.

1st & 2nd Effect Evaporator System

To de-bottleneck capacity of maintaining vacuum at high load, Stamicarbon recommended replacement of 2nd stageevaporator and some critical condensers/ejectors of the complete vacuum system. The equipment were procuredfrom Graham, USA & GR Engineering , Mumbai. Due to space constraint again, the erection of the equipment ofhigher dimensions and at a height of 25 mts was a difficult and challenging job. Weight and size of the newequipment was more than the old one, so it was decided to change the load distribution pattern by resting theequipment on structural beams fixed to the vertical concrete columns instead of resting them on concrete floorsimilar to the old one. For achieving this task, a 200 tonne capacity crane was utilised by the erection contractorL&T to remove the existing equipment and installation of new ones. GDC the civil contractor provided services for broadening the slots and making the equipment foundations suitable for changed dimensions. All the in-situ jobs ata height of 25 meters including equipment. erection was carried out in just 8 days.

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Prilling System

One of the biggest limitation at Kalol is its induced draft Prilling Tower which has a total free fall height of only 50mtrs having an internal diameter of 17 meters. Due to the Prill Tower size limitation, the prill temperature at thebottom of the tower remains in the range of 85-90oC even at plant capacity of 1200 mtpd specially in summer season.

To overcome this problem, fludized bed Prill Cooling System was installed in 1988 to get prill temperature of 60 -65 oC before sending the product to Silo / Bagging Plant . Taking advantage of the Prill Cooling System , Stamicarbon suggested installation of modified Prill Bucket to make existing Prill Tower suitable to achieve higherprill production rate with marginal sacrifice on prill size . Guaranteed size was 1.6 mm (mean prill dia) withrespect to 1.7 mm before revamp. During detailing, changing over to modified Prill Bucket also called forcomplete replacement of Prilling Machine which is supplied by Stamicarbon approved vendor MachinefabriekKreber of The Netherlands. The daily production of about 1750 MT is now being processed through the same 25year old Prilling Tower with mean prill dia of 1.4 - 1.5 mm.

DCS Based Instrumentation:

Under the expansion and modernisation scheme, 23 years old pneumatic instrumentation has been changed toMicroprocessor based instrumentation incorporating Distributed Control System (DCS). Yokogawa’s Centum CSSystem has been selected. The system has many unique features like single loop integrity for controllers, hardwareon unix platform high resolution CRT and more user friendly man-machine interface. The system has window inwindow features, half size windows facility, four windows on single CRT screen facilitating modulation of 4x8 i.e.32 controllers from a single page. The system employs 84 nos. closed loops, 150 nos 4-20 mA open loops, 160 nostemperature open loops, 304 nos digital input loops and 64 nos digital output loops.

REPLACEMENT OF CONTROL VALVES

Total 21 Nos of Control Valves were procured from Parcol, Italy. Out of these , 10 control valves were meant forreplacement of existing ones and 11 for new installation. These were considered to match increased production andfacilitate safe and precise control of process parameters.

HAZOP STUDY

Hazop study of the plant was carried out by Stamicarbon to check the adequacy of existing high pressure system forrevamped capacity. After thorough checking of various high pressure equipment, piping and control valves, theConsultant certified that the incremental increase of system pressure by about 4 to 5 kg/cm2 after revamping will bewithin the safe operating limits.

TIE - IN POINTS:

As soon as various schemes were firmed up, it was decided to take Tie - In Points in the existing plant for hookingup of the schemes as and when the equipment were available. There were in all 140 Tie-In Points for whichmaterial was procured and arranged well in advance. The Tie- In connections were taken as and when opportunityarose in Urea plant during periodic shut downs. This strategy worked well as most of the schemes could be hookedup within the time schedule and in running plant. Other than the annual turn around, Urea plant was not shut downfor hooking up of any expansion scheme.

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UREA PLANT REVAMP COST Out of the total project cost of Rs 1497 Million (US $ 42.77 Million) for Kalol expansion project, the cost towardUrea plant revamp was Rs.598 Million (US $ 17.09 Million). Break-up is given in Table-3

0.32 11.2Control & Safety valves17.

0.19 6.6Instrument items such as Smart transmitters, I/P & P/I converters, Pressuregauges, Rotameters, Orifices, Magnetic Flowmeter Cabinets etc

16. 0.42 14.8Urea DCS 15. 0.08 2.8EOT Cranes14. 0.03 0.9Heat exchanger modification13. 0.09 3.1Chemical cleaning of Stripper 12. 0.26 9.1Modified reactor trays11.

0.28 9.9 N/C Ratio Meter & Water in Carbamate analyser

10.

0.06 2.2 Strong Ammonia Water Tank, Urea Solution Tank and Lean Carbamatevessel

9. 0.19 6.5LP Carbamate Condenser8.

0.11 4.0Urea solution pumps , Lean Carbamate pumps , Process water pumps & Atmos. Vent scrubber pumps

7. 0.58 20.4Evaporator package 6. 0.77 26.9Vacuum Condensing System 5. 0.27 9.3Prilling Machine with Prill Buckets 4.

1.19 41.7 HP Ammonia & Carbamate Pump with Variable Speed Drive & Drive conversion of existing pumps

3. 7.56 264.5CO2 Centrifugal Compressor package 2. 1.20 42.3 Design , Engineering & Consultancy fee 1.US$ MillionRs. Million

CostCost Item DescriptionSl.No

17.09 598.0 Total 0.52 18.2Insurance, Bank charges & Financing charges21. 0.51 17.7 Civil & Structural jobs20.

0.83 29.0Mechanical , Electrical & Instrumentation Erection Cost

19. 1.63 56.9Pipes, Fittings & Valves 18.

Conversion rate 1US$ = Rs. 35/- Table-3

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PERFORMANCE:

Plant was commissioned for revamped capacity in August ‘97 well within the cost & time schedule. Guarantee TestRun was successfully performed in February 1998 in presence of Stamicarbon & TICB engineers meeting all theguarantee figures as listed in Table - 4. Presently the plant is producing around 1750 MTPD on continuous basis andmaximum production achieved recently was 1800 MTPD.

408 179 KG/tonne of ureaLow pressure steam export5. 853 871KG/ton of Urea Sp. consumption of steam4. 733 737 KG/tonne of UreaSp. consumption of CO23. 566 570KG/ tonne of UreaSp. consumption of Ammonia2. 1690 1650 MTPDDaily production capacity1.

Achieved Figure

GuaranteedFigures

UnitDescriptionSl.No

Table - 4

ECONOMICS

The total capital cost for revamp of Ammonia & Urea plants at IFFCO Kalol was Rs. 1497 Million (US $ 42.77Million) out of which cost incurred for Urea plant expansion was Rs.598 Million (US $ 17.09 Million), which is 40% of the total revamp cost. The specific capital cost investment per tonne of urea for the incremental productionof 1,48,500 tonne per annum of urea at the total cost of Rs.1497 Million (US $ 42.77 Million) works out to Rs.10,080/- (US $ 288) as compared to Rs. 21,600/- (US $ 614) per tonne of urea for a 7,26,000 tonne annual capacitygrass root project, assuming present day investment of Rs. 15680 Million (US $ 448 Million).

CONCLUSION:

The successful revamping of 23 years Vintage Urea Plant at Kalol shows the possibility of revamping wellmaintained similar Urea Plants at a very reasonable cost. Last but not the least, judicious planning, training ofoperating & maintenance staff and proper selection of technology for revamp is a must.

• V.S. Vaish is General Manager at IFFCO, Kalol, who was involved in conceptualisation of expansion schemesand execution of the same as Project In-Charge.

• A.B. Sarkar is Sr. Manager (Project) at IFFCO Kalol, who was involved with process licensor, consultantand execution of Urea plant revamp jobs.

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